Why are older mothers more likely to have twins?
Hum Reprod 2006: 21: 1,531-2
Twins (dizygotic) are commoner in families with other twins. They are also more common when the mother is aged 36-39 years. This Dutch study looked at follicle development in 959 spontaneous ovulatory cycles of 507 women. This finding excludes pregnancies as a result of assisted reproduction and is surprising because it occurs at a time when natural fertility is declining.
No explanation for this has yet been found and so the markers used were multiple follicular growth and FSH levels.
The results are fascinating. It seems that higher FSH levels in the perimenopause cause more than one follicle to develop.
The authors describe this as an overshoot of the negative feedback mechanism.
As we were already aware, if two good-quality oocytes are produced, a twin pregnancy will result.
MRSA in the community
CMAJ 2006; 175: 145
Infection with a strain of Staphylococcus aureus unresponsive to commonly used antibiotics is a major fear of patients about to be admitted to hospital.
Increasingly MRSA infections are also occurring in the general population in patients who have not been in hospital. It is thought that some patients have a genetic predisposition, but that the real risk is that community-acquired infections may be mismanaged unless clinicians are aware of the possibility of MRSA.
This paper makes recommendations for treating MRSA infections and for preventing them.
Key preventive measures for infection control are hand washing and covering wounds already infected with MRSA. The authors also recommend avoiding the use of antibiotics for mild and superficial infections.
This guidance is as applicable in the UK as in Canada.
Psychological help for children with diabetes
BMJ 2006; 333: 65-8
Developing diabetes which requires regular injections of insulin is difficult for both adults and children. The alteration in lifestyle, and the need for regular injections and monitoring, cause distress.
In addition, if the control of blood sugar is not adequate there are effects on mood and well-being.
Patient education is of supreme importance, and psychological treatments in addition to education might be helpful.
This study is a meta-analysis of other work. It looked at the effect of different psychological interventions on blood sugar control. It was found that there is a weak but significant benefit to psychological help for children and adolescents, but no evidence that it is helpful in adults.
This information is useful in planning care for young diabetics.
Investigate rectal bleeding in patients over 45
BMJ 2006 333: 69-70
Current practice - as defined by NICE guidelines - is that patients aged over 40 with rectal bleeding and change in bowel habit lasting more than six weeks should be referred for investigation of suspected bowel cancer. Other signs such as anaemia or rectal mass are also indications for referral.
This recent prospective study looked at patients presenting in primary care with rectal bleeding. Cases were gathered over a period of 10 years.
Patients over 45 with rectal bleeding with or without change in bowel habit were investigated. Of these, 5.7 per cent were found to have colorectal cancer and 4.9 per cent had a colonic adenoma.
The authors suggest that patients with new-onset rectal bleeding should be investigated in the absence of other symptoms. They advise that the guidelines for referral of suspected cancer be changed.
- Dr Merriman is a GP in Oxford and a member of our team who regularly review the journals
- Older mothers more likely to have twins.
- MRSA can be prevented by avoiding use of antibiotics for mild or superficial infections.
- Diabetic children and adolescents can be helped by psychological treatments.
- New-onset rectal bleeding should be investigated in the absence of other symptoms.
RESEARCH OF THE WEEK
More reason to fear a second heart attack
Heart 2006; 92: 973-4
Angina preceding a heart attack can protect the heart against some damage through the mechanism of ischaemic preconditioning. It seems that heart muscle has a method of protecting itself when there is occlusion of an artery if it has had a period of adaptation with arterial narrowing.
Once infarction occurs, this heart repair mechanism is lost. This means that if there are further anginal attacks they will not be protective against a second MI.
In practical terms this reinforces our clinical experience that patients who have had a single MI are less likely to survive a second and that angina in a patient who has had an MI should always be taken seriously.